Integrated circuits connected to a power supply consume power while being in use or on-line. An estimation of the current flowing through the integrated circuit or a portion of the integrated circuit or module or device on the integrated circuit die is an important factor for validation of the integrated circuit. On-line current estimation, i.e., estimation of the current during operation of the integrated circuit, on supply lines which provide power from a power supply connected to power supply pins of the integrated circuit to the circuit or regions or modules of the circuit is an important aspect of validation and power management of the integrated circuit. Power management may, for example, be applied in the case of multiple gated power domains. On-line current estimation may influence, for example, optimization of software for employing the integrated circuit. An integrated circuit may, for example, comprise a processing device.
In U.S. Pat. No. 6,933,739, an integrated circuit is described wherein absolute values of voltage, temperature and silicon quality at certain locations on an integrated circuit die are determined by means of testing devices, such as ring oscillators, placed at the various locations.
In U.S. Pat. No. 7,443,187, a technique for on-chip detection of integrated circuit power supply noise is described wherein monitored signals on integrated circuit power supply lines are voltage level shifted and compared with a voltage of a reference power supply line using analogue comparator circuits.
In U.S. Pat. No. 7,250,783, leakage current in electronic devices, such as microprocessors, is measured in multiple locations on the integrated circuit die using a current mirror multi-channel leakage current monitor circuit.
In JP 06-148264, a measuring method for leakage current of an integrated circuit device is presented. To determine accepted or rejected products, a resistance and a relay are connected in series with a power supply pin and a comparator for evaluating voltage drops caused by leakage current. The method allows for externally measuring overall leakage current.